Apparatus for determining the tendency of paper to curl



April 13, 1943. G. s. WITHAM, JR ,3 APPARATUS FOKDETERHINING THE TENDENCY OF PAPER To CURL Filed Oct. 23, 1940 ATTO/PNEY Patented Apr. 13, 1 943 i i 2,316,378

UNITED STATES PATENTOFFICE APPARATUS FOR DETERMINING THE TEND- ENCY OF PAPER, TO CURL George S. Witham, Jr., Hudson Falls, N. Y., as-

signor to W. & L. E. Gurley, Troy, N. Y., a corporation of New York Application October 23, 1949, Serial No. 362,396 c (mam Curling, or the tendency of paper to curl,"-"ma*- Fig;

elevation view thereof terlally affects its usefulness to the trade and taken in about the plane 2-2 of Fig. 1; papers which are manufactured at different times Fig.3 is an'elevation view of the front of the although they may be formed, as nearly as posdevice; slble, of the same composition and grade may Fig. 4 is a plan view of the support for the differ greatly in their tendencies to curl. paper specimen; and

Paper is ordinarily manufactured for certain Fig. 51s a wiring diagram for the electrical purposes. In many cases, the paper should be parts of the device. not only of theproper grade and'kind but the tend- Referring to the drawing in which I have i1- ency thereof to curl must fall within a very low, lustmted a Preferred embodiment f y invenallowable range or else the vpaper will not be action, I indicates generally a receptacle 0r 011 ceptable or suitable for the purpose intended. ing within which a sample of paper is adapted For example, in mimeograph work and high to be placed and subjected to heat of substanspeed flat bed printing presses with automatic tially a standard or constant, predetermined temfeeds, the paper which is supplied for use therein perature. The receptacle comprises a base 2, upmust have an extremely low tendency to curl standing end walls 3 and 4, side walls 5 and 6 since, otherwise, the automaticfee'ders will not and a cover 1 which is preferably removable and operate properly and inefficiency results. Furmay be hinged or otherwise suitably fastened to thermore, paper of low curling tendencies is quite the walls. The interior of the recept fi is p desirable even where used as forms, for example, 0 vided with a par it n 3 extending transversely in composition books, sales books and the like. thereof and subdividing the receptacle into two However, if during the process of,.manufacturcompartments 9 d The fi pa me t 9 is ing paper, the tendency to curl of the ultimate designed to be heated t0 a suitable, standard paper product can be determined, steps may be temperature to which the sample of paper is subtaken, for example, to modify the stock during jected for testing p po and the compartthe paper making process whereby materially to ment i designed O house a light Source which,

reduce and substantially to eliminate such tendthe present embodiment of y invention, is encyin th paper,. employed in determining the tendency of the It is, therefore, a first object of my invention 1 pap r sample to curl.

to provide an apparatus for determining the Since it is desirable to maintain a substantially tendency of paper to curl. More specifically, an constant or standard temperature in the comobject of my invention resides in providing an partment 9, the Walls including e t p and base apparatus in which the tendency to curl of paper 0f the receptacle are preferably formed of mamay be determined under standard temperature terial having f y good thermal insulating P pconditions and such tendency measured accorderties. On the base 2 of the receptacle and in ing to astandardized scale. compartment 9 are mounted sockets II and I2 More specifically, it is an object of my i nvenfor incandescent lamps l3 and M. The lamp tion to provide an apparatus wherein a sample l3 may, for examp be f a Watt ra ing and sheet of paper may be subjected to a standard lamp l4 may b of a 0 Wa r t Ab e or substantially constant, predetermined temper- 40 these lamps which are primarily ployed for atureand the actual curling of the paper measheating P p s I preferably D e a .bafl e l5 \n'ed on a scale. still more specifically, an obof asbestos or a material of like heat r sisting ject of my invention resides in providing an approperties which 15 supported by means of transparatus comprising an enclosure within which a versely extending bars I6 and I1. These bars specimen sheet may be subjected to heat of submay be fastened tovopposlte side walls 5 and 6 stantially a standard temperature, the temperaof the receptacle and the baflle I5 is preferably ture being thermostatically controlled and the spaced on all sides thereof from the side walls of curling of the paper under these conditions being the chamber 9. I

measurable directly on a scale." Above the bafile l5 are fastened two angle mem- I accomplish the foregoing objects by means of bers l8 and I9 which extend transversely of the the novel constructions and arrangementof elecompartment and are secured at one endto the ments described below and illustrated inthe acside wall 5 and terminate atthe other end in an companying drawing, in whichopening 20 (see Fig. 2) in the side wall 6. The

Fig. 1 is a sectional elevation view of a pre- 7 angle members 18 and [9 are adapted slidably to ferred form of my invention; support and guide a substantially flat plate element, preferably of fairly good heat conducting material, which is adapted to support the sample of paper for test purposes. The plate Il may be provided with runners II and II on the under surface thereof to engage the guides II and II and a strip I4 may be fastened beneath and in spaced relation to the plate II, as by means of screws II, to engage the bottoms of the guides II and II whereby slidably position thereon.

To one end of the plate II is fastened a cover plate II which is adapted to close the opening II in the side wall I of the receptacle when the plate II is substantially wholly inserted within the receptacle. To the plate II is fastened a handle I1 for operating the plate II. Adjacent the other end of the plate II is provided an upstanding plate-like element II which is adapted, when the plate II is practically wholly withdrawn through the opening II, to engage the side wall I about said opening I and effect a substantial closure thereof. The plate II is preferably provided in order to prevent the escape of heat from the compartment I and a resulting drop in temperature therein when the plate II is withdrawn for purposes of placing a specimen or sample of paper thereon.

Within the comaprtment I and preferably at about the elevation of the plate II is disposed a thermostat II which. as hereinafter more fully explained, is connected in circuit with the lamp l4. The lamp II is preferably so arranged as to be continuously energized while the apparatus is in operation while the lamp I4 is thermostatically controlled whereby to maintain a substantially constant and standard temperature within the compartment 9.

In compartment II is mounted a lamp socket II which is adapted to receive an incandescent lamp II of the type which will provide substantially a point source of light. Since incandescent lamps of this character are ordinarily of a six volt rating, a transformer I2 is provided for transformation purposes. In the embodiment illustrated, a mirror II, mounted on a removable support I4, is arranged to reflect the light cast thereupon from the light source or lamp II through a plane-convex lens II which is mounted in an aperture II in the partition I. The lens II is a collimating lens which casts light from the light source in parallel rays across'the compartment I. The lens and plate-like element II which support the specimen of paper are so arranged that the light rays from the lens will be substantially parallel with the element II or the specimen paper supported thereon and will be intercepted by the specimen.

In the end wall I of the compartment I of the receptacle is disposed preferably a ground glass target I1. The target is so arranged with respect to the lens 35 and supporting plate II that a specimen of paper on the plate II will intercept the light rays and the shadow thereof will be cast upon the target. The target is provided with a scale II. Preferably, the lowest calibration of the scale, marked "100" in Fig. 3, is so positioned that the shadow of a sample sheet of paper lying upon the supporting plate II will coincide therewith. However, if the paper should curl, its

shadow will correspondingly move upwardly on the scale II and the degree to which the paper curls may-be determined from the scale. Preferably, the scale is calibrated in terms of degree to hold the plate II in of flatness of the paper as indicated. In other words, if the paper should not curl, its shadow will remain coincident with the calibration marked 100" and it will have 100% fla ness. If. however, the side edges thereof should curl sufficiently to cause the shadow thereof on the target to coincide with the calibration II, for example. it would have a flatness of only The plate-like element II for supporting the paper samples, which is illustrated in plan in Fig. 4. is preferably provided on its upper surface with a lone marking II which d signates the p o r location of the sample for testing p poses.

Atoggle switch 4I maybelocated atthefront of the receptacle and a plug connector 4| connected with a lead 4I which connects with the wiring in Pig. 5. that conductors 48 and 44 of the lead 4I are connected with the service mains 4! and 4I by means of the plug connector 4|, a circuit will be established. if the switch 0 is closed, to the transformer II and lamp II, transformer II and lamp II being across the conductors 43 and 44. Lamp l4 and themestat II are connected in series between conductors 4I and 44 and, hence, thermostat II serves to control the energiation of lamp l4. The lamp II is connected across the transformer II from which it receives its en An opening 41 may be provided in side wall I of the compartment I to provide access to the inttgior thereof, and a door 48 associated there- '1 1 To determine the tendency of paper to curl, the apparatus is electrically connected with the supply mains and the compartment I thereof facturing the paper, which is preferably of example, it may be 4" a sample may be taken standard dimensions, for x 4" square and placed I upon the zone designated on the supporting plate II. For this purpose. the plate II is withdrawn through the opening II, the paper placed thereupon in correct position, and the plate II reinserted to position the sample ency to curl or, at the most, a tendency which is well within the permissible range;

It will be understood that although I have described my invention in connection with its use in determining the tendency of paper to curl, it may likewise be employed for determining like tendencies in other materials.

Although I have illustrated and described the use of incandescent lamps as heating means, it will be understood that any suitable heating means may be employed such as heating coils. Coils may be employed which are adapted to be threaded in sockets of the character illustrated.

Furthermore, it will be understood that one or a plurality of heating means may be used and that one or any number, or all, of such heating means may be thermostatically controlled.

While I have described my invention in its preferred embodiments, it is to be understood that the words which I have used are words of description rather than of limitation. Hence, changes within the purview of the appended claims may be made without departing from the true scope and spirit of my invention in its broader aspects.

What I claim is:

1. In a device for determining the curling properties of paper and the like, means forming upon said scale, and means for providing heat an enclosure provided therewithin with means adapted freely to support-thereon a sample sheet of paper in substantially horizontal, fiat condition and means for providing and maintaining within said enclosure-forming means heat of substantially a standard temperature, said enclosure-forming means being provided in a side thereof with a translucent target provided with a scale for measuring the flatness of said sample sheet and means for casting light rays upon said target; said paper-supporting means being arranged to support said paper in the path of said light rays whereby the shadow of said paper will appear on said target.

2. In a device for determining the curling properties of paper and the like, a translucent target provided with a scale, means including a light source disposed in spaced relation to said scale and arranged to cast light rays thereupon, means for collimating the rays of light from said light source and means for so supporting a sample sheet of paper substantially parallel to and in light-intercepting relation to said light rays when so collimated whereby to provide the edgewise shadow of said paper on said scale, and means for providing heat of substantially a standard temperature to said sample sheet.

3. In a device for determining the curling properties of paper and the like, means forming an enclosure provided therewithin with means adapted freely to support thereon a sample sheet of paper in substantially horizontal, fiat condition, a translucent target mounted in a wall of said enclosure and provided with a scale, a light source disposed in spaced relation to said targetand arranged to cast light rays thereupon. means for collimating the rays of light from said light source, said sheet-supporting means being arranged to support a sample sheet of paper substantially parallel to and in light-intercepting relation to-said light rays when so collimated whereby to provide the edgewise shadow of said paper on said scale, and means disposed within said enclosure-forming means for providing heat of substantially a standard temperature to said sample sheet.

4. In a device for determining the curling propof substantially a standard temperature for heating said sample sheet.

5. In a device for determining the curling properties of paper and the like, a scale, means disposed in spaced relation to said scale for casting light rays thereupon, means for freely supporting a sample sheet of paper in substantially initially fiat, horizontal position in the path of said light rays and in substantially parallel relation thereto whereby to cast the shadow of said sample sheet edgewise upon said scale, and means for providing heat of substantially a standard temperature for heatingsald sample sheet.

6. In a device for determining the curling properties of paper and the like, a scale, means disposed in spaced relation to said scale for casting light rays thereupon, means for supporting a sample sheet of paper in the path of said light rays and in substantially parallel relation thereto whereby to cast the shadow of said sample sheet upon said scale, means forming an enclosure for said sample sheet and supporting means therefor through which said light rays may pass to said scale, and means for providing substantially standard temperature conditions within said enclosure.

7. In a device for determining the curling properties of paper and the like, a translucent target provided with a scale for observing and measuring the curl of a sample sheet of paper, a light source disposed in spaced relation to said target and arranged to cast light rays thereupon, means for freely supporting a sample sheet of paper in substantially flat condition in the path of said light rays and in substantially parallel relation thereto whereby to cast the shadow of said sample sheet edgewise upon said scale and in alignment with one of the calibrations of said scale, and means for providing heat of substantially a standard temperature for heating said sample sheet.

8. In a device for determining the curling properties of paper and the like, means forming an enclosure provided therewithin with means adapted freely to support thereon a sample sheet of paper in substantially horizontal, flat condition, a scale and means disposed in spaced relation to said scale for casting light rays thereupon; said scale, sheet-supporting means and last mentioned means being so constructed, correlated and arranged as to cast the edgewise shadow of said sample sheet upon said scale, and means for providing heat of substantially a standard temperature to the sample sheet.

9. In a device for determining the curling properties of paper and the like, means forming an enclosure having an opening therein, a scale,

means disposed in spaced relation to said scale for casting light rays thereupon, movable means for supporting'a sample sheet of paper in the path of said light rays and in substantially parallel relation thereto whereby to cast the shadow of said sample on said scale, said supporting means being movable into and out of said enclosure through said opening therein, means for closing said opening when said supporting means is substantially wholly inserted in said enclosure.

and means for providing substantially standard temperature conditions within said enclosure.

10. In a device for determining the curling properties of paper and the like means forming an enclosure having an opening therein, a scale, 5

means disposed in spaced relation to said scale for casting lizht rays thereupon, means slidably mounted within said enclosure for supporting a sample sheet oi paper in free, flat condition thereupon and in the path of said light rays and 10 in substantially parallel relation thereto whereby to cast the shadow 0! said sample on said scale. said supporting means being slidable into and out of said enclosure through said opening therein, means for closing said opening when said supporting means is substantially wholly inserted in said enclosure, and means for providing substantially standard temperature conditions within said enclosure.

GEORGE B. WI'I'HAM, Ja. 

